CVE-2018-5709 [High] | Integer Overflow in Kerberos

An issue was discovered in MIT Kerberos 5 (aka krb5) through 1.16. There is a variable "dbentry->n_key_data" in kadmin/dbutil/dump.c that can store 16-bit data but unknowingly the developer has assigned a "u4" variable to it, which is for 32-bit data. An attacker can use this vulnerability to affect other artifacts of the database as we know that a Kerberos database dump file contains trusted data.

#	Date	Old EPSS score	New EPSS score	Delta (New - Old)
1	2026-06-15	1.64%	2.11%	+0.47%
2	2026-05-30	1.38%	1.64%	+0.26%
3	2026-05-16	—	1.38%	—

Date

Old EPSS score

New EPSS score

Delta (New - Old)

2026-06-15

1.64%

2.11%

+0.47%

2026-05-30

1.38%

1.64%

+0.26%

2026-05-16

—

1.38%

—

Base score	Version	Severity	Vector	Exploitability	Impact	Score source
7.5	3.0	HIGH	`CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N` Click to expand Attack vector (AV:N) Could be attacked over the internet or any normal routed network—not just someone sitting at the machine. Attack complexity (AC:L) Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup. Privileges required (PR:N) No account or special rights needed—anonymous or random user is enough. User interaction (UI:N) Nobody has to click “OK” or open a trap file; it can work without a victim helping. Scope (S:U) Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems. Confidentiality (C:N) Doesn’t really leak secrets in a meaningful way. Integrity (I:H) They could widely tamper with or forge data—trust in the data is badly hurt. Availability (A:N) Service keeps running; no real outage angle.	3.9	3.6	[email protected]
5.0	2.0	MEDIUM	`AV:N/AC:L/Au:N/C:N/I:P/A:N` Click to expand Access vector (AV:N) Can be exploited remotely over network reachability. Access complexity (AC:L) Exploitation conditions are straightforward and predictable. Authentication (AU:N) No authentication is required. Confidentiality impact (C:N) No confidentiality impact. Integrity impact (I:P) Partial integrity impact. Availability impact (A:N) No availability impact.	10.0	2.9	[email protected]

Base score

Version

Severity

Vector

Exploitability

Impact

Score source

7.5

3.0

HIGH

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N Click to expand

Attack vector (AV:N): Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L): Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N): No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N): Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U): Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N): Doesn’t really leak secrets in a meaningful way.
Integrity (I:H): They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:N): Service keeps running; no real outage angle.

3.9

3.6

[email protected]

5.0

2.0

MEDIUM

AV:N/AC:L/Au:N/C:N/I:P/A:N Click to expand

Access vector (AV:N): Can be exploited remotely over network reachability.
Access complexity (AC:L): Exploitation conditions are straightforward and predictable.
Authentication (AU:N): No authentication is required.
Confidentiality impact (C:N): No confidentiality impact.
Integrity impact (I:P): Partial integrity impact.
Availability impact (A:N): No availability impact.

10.0

2.9

[email protected]

OS Trackers for CVE-2018-5709

vendor	priority	summary	link
`alpine`	high	CVE-2018-5709: 1 source package rows (krb5); 10 state rows across 10 repos (3.10-main, 3.11-main, 3.12-main, 3.17-main, 3.18-main, 3.19-main, 3.20-main, 3.21-main, 3.22-main, edge-main); fixed 10, open 0.	https://security.alpinelinux.org/vuln/CVE-2018-5709
`debian`	unimportant	CVE-2018-5709 unimportant priority: Debian including 1 source packages (krb5), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): open 5.	https://security-tracker.debian.org/tracker/CVE-2018-5709
`redhat`	—	—	https://access.redhat.com/security/cve/CVE-2018-5709
`suse`	medium	CVE-2018-5709 severity moderate: SUSE including 13 source package names (krb5, krb5-32bit, …), 125 product×package rows across 35 product lines (Magnum Orchestration 7, SLES for SAP Applications 11 SP3, … (35 product lines)): Known Not Affected 125.	https://www.suse.com/security/cve/CVE-2018-5709/
`ubuntu`	negligible	CVE-2018-5709 negligible priority: Ubuntu including 1 source packages (krb5), 13 status rows across 13 suites (artful, bionic, cosmic, disco, eoan, focal, groovy, hirsute, impish, jammy, trusty, upstream, xenial): ignored 12, deferred 1.	https://ubuntu.com/security/CVE-2018-5709

Affected software / configurations for CVE-2018-5709

Vendor	Product	Version	Raw CPE
mit	kerberos	<= 5-1.16	cpe:2.3:a:mit:kerberos::::::::

References for CVE-2018-5709

URL	Tags
https://github.com/poojamnit/Kerberos-V5-1.16-Vulnerabilities/tree/master/Integer%20Overflow	Third Party Advisory
https://lists.apache.org/thread.html/rf9fa47ab66495c78bb4120b0754dd9531ca2ff0430f6685ac9b07772%40%3Cdev.mina.apache.org%3E

URL

CVE-2018-5709

Exploit prediction scoring system (EPSS) score for CVE-2018-5709

Common vulnerability scoring system (CVSS) metrics for CVE-2018-5709

Weakness enumeration for CVE-2018-5709

OS Trackers for CVE-2018-5709

Affected software / configurations for CVE-2018-5709

References for CVE-2018-5709